The number of integral terms in expansion $(\sqrt [2]{3} + \sqrt [ 8 ]{ 5 } )^{256}$ is

$z=2 x+3 y$

$f\left(x\right)=\left(2-\frac{3}{x}\right)^{15}$

If the sum of the coefficients in the expansion of $(l^2x^2-2lx+1)^{50}$ vanishes then $l$ is equal to: